Utilization of Laparoscopic and Open Inguinal Hernia Repair: A Population-Based Analysis

Introduction

Laparoscopic inguinal hernia repair is a safe, effective treatment for inguinal hernias.^1,2 For initial inguinal hernias, complication and recurrence rates for laparoscopic repair are comparable to open repair, ³ particularly for experienced surgeons. ⁴ While laparoscopic repair for unilateral and initial hernias remains controversial, however, many argue that laparoscopic repair is the preferred approach for bilateral and recurrent inguinal hernias.^5–7 Although laparoscopic inguinal hernia repair was developed more than two decades ago, little is known about its utilization. Some reports suggest that 10–20% of inguinal hernias are repaired laparoscopically,^8–10 but no large population-based studies have been published. Further, we know little about the clinical context in which surgeons are more likely to perform laparoscopic repair. Specifically, we do not know if the laparoscopic approach is more commonly utilized for recurrent or bilateral inguinal hernias. To describe the use of laparoscopy for inguinal hernia repair, we performed a population-based study of outpatient inguinal hernia repairs in Florida in 2002 and 2003. We compared utilization of laparoscopic and open surgery, as well as patient demographics, indication for procedure, location of procedure (i.e., hospital or ambulatory surgery center), and charges associated with these two surgical approaches.

Methods

We performed a retrospective, population-based cohort study of all outpatient inguinal hernia repairs in Florida in 2002 and 2003. We gathered data from the State Ambulatory Surgery Database (SASD) from the Agency for Healthcare Research and Quality. The SASD is a group of administrative databases from certain states that contain demographic, clinical, and charge data for all ambulatory surgery performed in a specific state during a specific year. We chose Florida because it is one of the most populous states in the SASD, which recorded CPT codes for inguinal hernia repairs. From the SASD for Florida in 2002 and 2003, we selected all patients age 19 or older with a current procedural terminology (CPT) code for open or laparoscopic inguinal hernia repair, including both initial and recurrent hernias (CPT codes 49505, 49507, 49520, 49521, 49525, 49650, 49651, and 49659).

We compared demographic data (i.e., age, gender, race, and insurance status) as well as the year the procedure was performed. For all patients, we calculated a Charlson comorbidity index, based on ICD-9 diagnosis codes available in the database. Hernia repairs were classified as open or laparoscopic and initial or recurrent, using the corresponding CPT codes. Bilateral hernias were not addressed, as they were not adequately coded in the database.

The location in which the hernia repair was performed was classified as either a hospital or an ambulatory surgery center (ASC). For every patient, total charges were collected and utilized as a proxy for cost. In an attempt to control for comorbidities, we also selected a subgroup of patients with a Charlson comorbidity index of 0 and a single procedure code for laparoscopic or open inguinal hernia repair and compared charges for patients treated at hospitals and ASCs. Patient demographics, clinical data, location of procedure, and charges were analyzed for laparoscopic and open hernia repairs. Continuous variables were compared by using the Student's t-test, and categoric variables were compared by using the chi-square test. All statistical analyses were performed by using STATA Version 8.2 (StataCorp, College Station, TX).

Results

A total of 58,127 outpatient inguinal hernia repairs were performed in Florida in 2002 and 2003. Of these, 11,351 (19.5%) were performed laparoscopically. In 2002, 28,776 inguinal hernia repairs were performed, 5493 (19.1%) of which were laparoscopic, while in 2003, 29,351 hernia repairs were performed, of which 5858 (20.0%; P < 0.01) were laparoscopic. Characteristics of patients treated with laparoscopic and open repair are listed in Table 1. Patients treated laparoscopically were younger, with a mean age of 52.7 years, compared to 57.4 (P < 0.001) for open repair. Compared to patients undergoing open repair, patients treated laparoscopically were more likely to be female (15.5 versus 9.1%; P < 0.001). They were also more likely to be of white race (84.4 versus 79.3%) and less likely to be black (5.7 versus 6.4%) or Hispanic (6.1 versus 10.3; overall, P < 0.001). Insurance status differed as well, with laparoscopic patients more likely to have private insurance (62.0 versus 47.2%) and less likely to be insured by Medicare (24.6 versus 36.8%; overall, P < 0.001).

As shown in Table 2, patients treated laparoscopically tended to be healthier, with a larger percentage of patients having a Charlson comorbidity index of 0 (90.0 versus 88.5%; P < 0.001). Nonetheless, both groups were quite healthy, with over 97% of patients in each group having a Charlson index of 0 or 1. Clinical indication had a small, but statistically significant, effect on the type of repair performed (Table 3). A laparoscopic approach was utilized for 19.4% of patients with an initial inguinal hernia, while a slightly larger percentage (20.5%; P < 0.001) of patients with a recurrent hernia were treated laparoscopically.

The percentage of repairs performed laparoscopically differed, depending on the type of health care facility (Table 4). At hospitals, 20.9% of outpatient inguinal hernia repairs were performed laparoscopically, compared to only 13.7% (P < 0.001) at ASCs. In addition, charges differed between the two types of procedures and the two types of institutions (Table 5). Overall, laparoscopic repairs resulted in higher charges ($12,087 vs. $7,580; P < 0.001). Charges for laparoscopic repairs were significantly lower at ASCs, however ($6,973 vs. $12,860; P < 0.001). For open repairs, procedures performed at ASCs also resulted in lower charges ($3,575 versus $8,584; P < 0.001). Within the subgroup of patients with a Charlson index of 0 and a single procedure code for inguinal hernia, charges were still significantly lower at ASCs, compared to hospitals for both open ($2,948 vs. $7,779; P < 0.001) and laparoscopic ($5,549 versus $11,587; P < 0.001) repairs.

Discussion

In this population-based study, almost 20% of all outpatient inguinal hernia repairs in Florida in 2002 and 2003 were performed laparoscopically. Although recurrent inguinal hernia is considered, by some, to be an indication for laparoscopic repair,^5–7 we found only slightly greater utilization of the laparoscopic approach in patients with a recurrent hernia, compared to those with an initial hernia. Compared to patients undergoing open repair, those undergoing laparoscopic repair were more likely to be white and to have private insurance. Moreover, although charges for laparoscopic repairs were lower at ambulatory surgery centers, compared to hospitals, patients treated at ASCs were more likely to undergo an open repair.

Few population-based studies exist that document the utilization of the laparoscopic approach for inguinal hernia repair. Nilsson and Haapaniemi reviewed the Swedish Hernia Register, a prospectively collected registry of hernia repairs from 1992 to 1999, and found that although 20% of inguinal hernias were repaired laparoscopically in 1996, that percentage had decreased to 11% by 1999. ⁹ Kald et al., using the same database, reported that 10% of all unilateral inguinal hernias were repaired laparoscopically over that time period. ¹⁰ A study in the United States revealed similar results—14% of inguinal hernia repairs in 2003 were performed laparoscopically. ⁸ Our study showed slightly greater utilization of the laparoscopic repair, compared to these other studies. This may be due to both proliferation of laparoscopy for many general surgery procedures as well as improvement of the technique of laparoscopic inguinal hernia repair. Nonetheless, laparoscopy does not appear to have gained the widespread acceptance for hernia repair that has been seen for other procedures, such as cholecystectomy or Nissen fundoplication.

Our results suggest that clinical indication may not be the only factor determining operative approach. We suspected that for recurrent hernias, the incidence of laparoscopic repair would be higher, as many researchers recommend the laparoscopic approach for recurrent hernias.^5–7 Although statistically significant, the difference in utilization of laparoscopic repair for recurrent versus initial hernias was very small and of doubtful practical significance (20.5 versus 19.4%). Moreover, we observed demographic differences in the utilization of laparoscopic repair. Patients were more likely to receive a laparoscopic repair if they were female, white, or had private insurance, which are demographic characteristics often associated with better health status. Because laparoscopy typically requires general anesthesia, many advocate directing less healthy patients toward an open procedure. However, our data do not support health status as an important factor influencing utilization of the laparoscopic approach. Although the laparoscopic group had slightly lower Charlson comorbidity indices, this again has little clinical importance, as more than 97% of patients in both groups had Charlson scores of 0 or 1.

Both surgeon and patient factors may influence these findings. Laparoscopic inguinal hernia repair is difficult to learn, and this learning curve may serve as a barrier to its widespread adoption. ¹¹ Moveover, surgeons who do not perform laparoscopic inguinal hernia repairs regularly may not be comfortable in using that method for recurrent repairs, thus steering their patients toward the open approach. Surgeon financial factors must also be considered. Laparoscopic repair typically takes more time and is reimbursed less than open repair, further influencing surgeon decision making. And, although laparoscopy is not indicated in one demographic group over another, more affluent, better-educated patients may desire laparoscopy, either requesting the laparoscopic approach or seeking out a surgeon who performs laparoscopy.

Our findings also show higher charges for laparoscopic repairs, compared to open. The large cost discrepancy could be partially explained by a larger percentage of laparoscopic patients undergoing bilateral repair, but this is unlikely to account for the entire difference seen. These results echo prior studies, in which laparoscopic inguinal hernia repair had higher up-front costs, but with quicker return to productivity.^12,13 Moreover, total charges were lower for both laparoscopic and open repairs at ASCs, compared to hospitals, even when comparing a subset of the healthiest patients. This is consistent with a prior study comparing laparoscopic cholecystectomies at hospitals and ASCs and likely reflects the higher operating expenses at hospitals. ¹⁴ Interestingly, patients in our study treated at ASCs were more likely to have an open hernia repair. One possible explanation is that ASCs are more cost-conscious than hospitals, and the open approach is preferred due to its assumed lower cost and faster turnaround. One recent study in Alabama, however, found laparoscopic inguinal hernia repair to be more profitable than open repair in a single ASC. ¹⁵ Without cost data, we are unable to determine definitively if this was the case in our study population.

Our study was not without limitations. First, we report data for a 2-year period in one only state, Florida, which is not necessarily generalizable to other parts of the United States or the world. We chose Florida because it is one of the more populous states in the SASD and has CPT coding data (as opposed to less-specific ICD-9 coding) for laparoscopic and open inguinal hernia repair. We chose 2002 and 2003 because those were the most recent years with complete data available at the time of the analysis. Second, although our dataset contained a large number of patients, the level of clinical detail was limited. We had no data on bilateral hernias (another common indication for laparoscopic repair), recurrence rates, or the laparoscopic approach used (i.e., transabdominal or totally extraperitoneal). Although this information is of clinical interest, it was not available in this administrative database. Finally, we used charge data as a proxy for cost. Although charges do not directly reflect costs or reimbursement, they are closely correlated in terms of relative magnitude, and the large difference between laparoscopic and open repairs and hospitals and ASCs suggests that a significant cost difference exists. Nonetheless, these differences should be interpreted with caution due to the inherent limitations of charge data.

Conclusions

In summary, this large, population-based study of 58,127 outpatient inguinal hernia repairs performed in Florida in 2002 and 2003 shows that 19.5% of repairs were performed laparoscopically. Patients with recurrent hernias were only marginally more likely to undergo laparoscopic repair. The laparoscopic approach was more frequently used for patients who were white, female, and had private insurance. Charges for laparoscopic repair were lower at ambulatory surgery centers, but the laparoscopic approach was less frequently used in that setting. These findings suggest that although clinical indications play a role, the use of laparoscopy for inguinal hernia repair may also be influenced by financial considerations.